Precise rotating mirror with near-zero longitudinal displacement based on driving force decoupling

Abstract

The present application relates to the technical field of space gravitational wave detection, and more particularly to a near-zero longitudinal displacement precision rotating mirror based on decoupling of driving force, comprising a one-dimensional angle deflection unit, a shell, a mirror, a redundant driving unit, a differential lever and a decoupling arm; the one-dimensional angle deflection unit comprises a rigid base and a deflection arm, the rigid base is rotationally connected with the shell, and the mirror and the deflection arm are respectively arranged on two sides of the rigid base; the redundant driving unit is installed on the shell, the differential lever is connected with a driving end of the redundant driving unit, and the decoupling arm is connected between the differential lever and the deflection arm; the differential lever is arranged perpendicularly to the deflection arm, and the decoupling arm is arranged perpendicularly to the differential lever and the deflection arm; the present application is used for overcoming the problem that the existing rotating mirror device has a large longitudinal parasitic displacement in the measurement process, and can improve the stability of the rotating center of the rotating mirror device, reduce the longitudinal parasitic displacement, reduce the error and improve the measurement accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of space gravitational wave detection, and particularly relates to a near-zero longitudinal displacement precision rotating mirror based on driving force decoupling. BACKGROUND

[0002] In space gravitational wave measurement, the near-zero longitudinal displacement precision rotating mirror is used as a front pointing mechanism, which is mainly used for compensating for the light beam transmission time delay caused by long distance between stars. Due to the position and role characteristics of the front pointing mechanism in the light path, the optical path change caused by the front pointing mechanism cannot be inhibited in the common light path, and the optical path change caused by the movement of the front pointing mechanism will directly manifest as noise of the gravitational wave signal. The existing rotating mirror device has unstable rotating center during driving, and is always accompanied by parasitic force and parasitic movement, so that the rotating mirror device has large longitudinal parasitic displacement and generates optical path error, and the noise formed will cover the gravitational wave signal to be measured, thereby affecting the measurement precision and causing measurement error. SUMMARY

[0003] The present application provides a near-zero longitudinal displacement precision rotating mirror based on driving force decoupling to overcome the problem of large longitudinal parasitic displacement of the existing rotating mirror device during measurement, so as to improve the stability of the rotating center of the rotating mirror device, reduce the longitudinal parasitic displacement, reduce the error, and improve the measurement precision.

[0004] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a near-zero longitudinal displacement precision rotating mirror based on driving force decoupling, comprising a one-dimensional angle deflection unit, a shell, a reflecting mirror, a redundant driving unit, a differential rod and a decoupling arm; the one-dimensional angle deflection unit comprises a rigid base and a deflection arm, the rigid base is rotationally connected with the shell, and the reflecting mirror and the deflection arm are respectively arranged on two sides of the rigid base; the redundant driving unit is installed on the shell, the differential rod is connected with the driving end of the redundant driving unit, and the decoupling arm is connected between the differential rod and the deflection arm; the differential rod is arranged perpendicularly to the deflection arm, and the decoupling arm is arranged perpendicularly to the differential rod and the deflection arm.

[0005] Further, a rigid frame is arranged between the shell and the rigid base, and the rigid frame is rotationally connected with the rigid base through two spoke type flexible hinges.

[0006] Further, the two spoke type flexible hinges are symmetrically arranged on the rigid frame, and the axes of the two spoke type flexible hinges pass through the center of the mirror surface of the reflecting mirror.

[0007] Further, the connecting surface of the rigid frame and the shell is arranged in parallel with the mirror surface of the reflecting mirror.

[0008] Furthermore, the decoupling arm is a multi-segment flexible structure.

[0009] Furthermore, the end of the decoupling arm connected to the swing arm is provided with a connecting seat, the connecting seat is provided with two plugs, the swing arm is provided with two holes, and the plugs are installed into the holes.

[0010] Furthermore, the redundant drive unit includes two actuators, the drive ends of the two actuators are connected to both ends of the differential lever, and the decoupling arm is connected to the center of the differential lever.

[0011] Furthermore, the differential lever is flexibly connected to the actuator.

[0012] Furthermore, an angle deflection monitoring unit is provided between the tilting arm and the housing, and the angle deflection monitoring unit is used to measure the deflection angle of the reflector.

[0013] Furthermore, a thin metal sheet is provided between the yaw arm and the angle deflection monitoring unit.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] This invention provides a near-zero longitudinal displacement precision rotating mirror based on driving force decoupling. A redundant driving unit drives a differential rod, which in turn drives a decoupling arm to rotate, thereby rotating the reflector to adjust its deflection angle. The structural arrangement of the differential rod, decoupling arm, deflection arm, and reflector ensures that the driving force on the deflection arm is parallel to the reflector surface. This eliminates the component of the driving force in the longitudinal displacement direction during the reflector's angle deflection, thus reducing the longitudinal parasitic displacement of the reflector during angle deflection, reducing measurement errors, and improving measurement accuracy. Attached Figure Description

[0016] Appendix Figure 1 This is an exploded view of the near-zero longitudinal displacement precision rotating mirror in this invention;

[0017] Appendix Figure 2 This is a schematic diagram of the near-zero longitudinal displacement precision rotating mirror in this invention;

[0018] Appendix Figure 3 This is a schematic diagram of one of the states of the swing arm rotation in this invention.

[0019] Reference numerals: 1-Rigid frame; 2-Rigid base; 3-Flexible hinge; 31-Upper spoke-type flexible hinge; 32-Lower spoke-type flexible hinge; 4-Swing arm; 5-Differential lever; 6-Decoupling arm; 7-Ceramic block; 71-Lower alumina ceramic block; 72-Upper alumina ceramic block; 8-Actuator; 81-Lower actuator; 82-Upper actuator; 9-Displacement sensor; 91-Right displacement sensor; 92-Left displacement sensor; 10-Housing; 11-Reflector; 12-Fastener; 13-Actuator fixing component. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The present invention will be described in one embodiment below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only and represent schematic diagrams, not actual pictures, and should not be construed as limiting the present patent. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the actual product size. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0021] like Figures 1-2 As shown, this embodiment provides a near-zero longitudinal displacement precision rotating mirror based on driving force decoupling, including a one-dimensional angle deflection unit, a housing, a reflector, a redundant drive unit, a differential rod, and a decoupling arm; the one-dimensional angle deflection unit includes a rigid base and a swing arm, the rigid base is rotatably connected to the housing, and the reflector and the swing arm are respectively disposed on both sides of the rigid base; the redundant drive unit is mounted on the housing, the differential rod is connected to the drive end of the redundant drive unit, and the decoupling arm is connected between the differential rod and the swing arm; the differential rod is arranged perpendicular to the swing arm, and the decoupling arm is arranged perpendicular to both the differential rod and the swing arm.

[0022] It should be noted that in this embodiment, a redundant drive unit drives the differential lever, which in turn drives the decoupling arm to rotate, thereby rotating the reflector to adjust the deflection angle. This means that by continuously rotating the reflector, the unavoidable swaying in the entire optical path is counteracted. Simultaneously, the structural arrangement of the differential lever, decoupling arm, deflector, and reflector ensures that the driving force on the deflector is parallel to the reflector surface. This means that the driving force remains parallel to the mirror surface during the circular motion of the deflector around its rotation center, and is always tangential to the circumference. This allows the redundant drive unit to achieve one-dimensional angular deflection. The torque applied by the unit is always a pure torque, that is, the torque is the product of the lever arm and the force vector. When the force driving the rotating shaft to rotate is kept along the tangent direction of the rotation at a position where the lever arm length is not zero, the torque is a pure torque. In other words, this torque only produces rotation. In this embodiment, the driving force on the yaw arm is parallel to the mirror surface, which enables the mirror to only rotate and not translate longitudinally. This eliminates the component of the driving force in the longitudinal displacement direction of the mirror during the angle deflection process, thereby reducing the longitudinal parasitic displacement of the mirror during the angle deflection process, reducing measurement error, and improving measurement accuracy.

[0023] like Figures 1-2 As shown, specifically, the one-dimensional angle deflection unit in this embodiment is preferably an integrally formed structure, which includes a rigid base 2, a two-spoke flexible hinge 3, a rigid frame 1, and a deflection arm 4. The two-spoke flexible hinge 3 is divided into an upper spoke flexible hinge 31 and a lower spoke flexible hinge 32. The connection relationship of each component is as follows:

[0024] In this embodiment, the reflector 11 is bonded to the rigid base 2. The rigid base 2 is connected to two spoke-shaped flexible hinges via two rotating shafts. The two spoke-shaped flexible hinges are symmetrically arranged, that is, the axes of the two spoke-shaped flexible hinges coincide, and the axes of the two spoke-shaped flexible hinges pass through the center of the mirror surface of the reflector 11. The high rotational accuracy of the two spoke-shaped flexible hinges can be used to keep the rotation center stable near the mirror surface of the reflector 11 during rotation, thereby reducing the longitudinal parasitic displacement on the reflector 11.

[0025] Preferably, the two spoke-shaped flexible hinges are set on the upper and lower end faces of the rigid frame 1, that is, the upper spoke-shaped flexible hinge 31 is located at the upper end of the rigid frame 1, and the lower spoke-shaped flexible hinge 32 is located at the lower end of the rigid frame 1.

[0026] The rigid frame 1 is installed to the housing 10 by fasteners 12. Preferably, the connection surface between the rigid frame 1 and the housing 10 is set opposite to the mirror surface of the reflector 11, so that the connection surface between the rigid frame 1 and the housing 10 is parallel to the mirror surface of the reflector 11, and the connection surface between the rigid frame 1 and the housing 10 is as close as possible to the mirror surface of the reflector 11. That is, when the one-dimensional angle deflection unit undergoes thermal deformation, the connection surface is parallel to the mirror surface to ensure the symmetry of thermal expansion. The connection surface is as close as possible to the mirror surface to make the plane where the fastener is located coincide with the mirror surface, so that the center of thermal expansion can be close to the center of the mirror surface, which helps to eliminate the longitudinal displacement of the mirror surface caused by thermal deformation.

[0027] One end of the tilting arm 4 is connected to the side of the rigid base 2 where the reflector is not bonded. Preferably, the tilting arm 4 and the rigid base 2 are integrally formed. The other end of the tilting arm 4 is connected to the driving force decoupling unit. The force transmitted by the driving force decoupling unit drives the rigid base 2 to rotate the reflector 11 one-dimensionally around the axis of the two-spoke flexible hinge. At the same time, the end of the tilting arm 4 is provided with a metal sheet for use with the angle deflection monitoring unit to measure the rotation angle of the reflector 11. In this embodiment, the motion plane of the tilting arm 4 is perpendicular to the mirror surface of the reflector 11 and perpendicular to the axis of the two-spoke flexible hinge. The motion plane of the tilting arm 4 passes through the center of the mirror surface of the reflector 11 to reduce the longitudinal parasitic displacement on the reflector 11.

[0028] Meanwhile, in this embodiment, it is preferable to design a small rotational stiffness in the direction in which the two spoke-shaped flexible hinges rotate around the axis, and a large longitudinal displacement stiffness in the direction perpendicular to the mirror surface of the reflector 11, so that the longitudinal parasitic displacement generated when the rigid base 2 is subjected to parasitic force perpendicular to the mirror surface of the reflector 11 is small, thereby reducing measurement error.

[0029] like Figures 1-2 As shown, specifically, in this embodiment, the redundant drive unit includes two actuators 8, two ceramic blocks 7, and actuator fixing members 13. The two actuators 8 are a lower actuator 81 and an upper actuator 82, and the two ceramic blocks 7 are a lower alumina ceramic block 71 and an upper alumina ceramic block 72. One end of the lower actuator 81 is provided with a lower alumina ceramic block 71, and one end of the upper actuator 82 is provided with an upper alumina ceramic block 72. The other ends of the two actuators 8 are mounted on the outer casing 10 through the actuator fixing members 13.

[0030] In this embodiment, the actuator 8 in the redundant drive unit can be a stacked piezoelectric ceramic, a voice coil motor, a stepper piezoelectric actuator, or a micro stepper motor. The stacked piezoelectric ceramic is wrapped with deformable silicone rubber and bonded to the outer shell. The voice coil motor, the stepper piezoelectric actuator, or the micro stepper motor is bonded, welded, or connected to the outer shell 10 by fasteners. This embodiment uses a redundant drive unit to improve the measurement reliability of the device. At the same time, the structure is compact and can further meet the aerospace adaptability testing requirements. It is especially suitable for small-sized ultra-high optical path stability rotating mirror devices mounted on spacecraft platforms.

[0031] like Figures 1-2 As shown, specifically, in this embodiment, the decoupling arm 6 serves as the driving force decoupling unit. The decoupling arm 6 is a multi-segment orthogonally distributed flexible structure, preferably a multi-segment orthogonally distributed flexible structure with 4 segments or more than or equal to 2 segments. Meanwhile, the decoupling arm 6 and the differential rod 5 are integrally formed.

[0032] The differential lever 5 is set perpendicular to the motion plane of the swing arm 4. The two ends of the differential lever 5 are respectively bonded to two ceramic blocks 7, that is, the differential lever 5 is connected to two actuators 8 through the two ceramic blocks 7 to prevent friction damage. When driving, either of the two actuators 8 can perform telescopic drive, and the other can be shut down and self-locked as a backup. The self-locked actuator is fixed in the lever of the differential lever 5, so that the actuator 8 can drive the differential lever 5 to move. When the actuator 8 used for telescopic drive fails and loses power, the failed actuator 8 is fixed in the differential lever 5, and the redundant backup actuator 8 starts and performs telescopic drive.

[0033] One end of the decoupling arm 6 is connected to the midpoint of the differential lever 5, and the other end of the decoupling arm 6 is connected to the yaw arm 4. Taking the decoupling arm 6 as a 4-segment structure as an example, each segment of the decoupling arm 6 is rigidly connected in two directions in three-dimensional space and flexibly connected in another direction. That is, it is rigidly connected in the direction perpendicular to the differential lever 5 and the yaw arm 4, and the flexural directions of two adjacent segments of the decoupling arm 6 are perpendicular to each other. This makes the overall structure of the decoupling arm 6 rigidly connected in the direction perpendicular to the differential lever 5 and the yaw arm 4, and flexibly connected in all directions perpendicular to the decoupling arm 6 itself. This is used to isolate parasitic forces and parasitic motions, so that when the resultant driving force of the differential lever 5 is applied to the yaw arm 4 through the decoupling arm 6, it is an approximately pure torque, which is used to reduce the longitudinal parasitic displacement on the reflector 11.

[0034] Meanwhile, in order to improve the connection stability between the decoupling arm 6 and the sway arm 4, and to reduce the concentrated stress of the decoupling arm 6 on the sway arm 4, this embodiment preferably provides a connecting seat at the end where the decoupling arm and the sway arm are connected. The connecting seat is provided with two plugs, and the sway arm is provided with two holes. The plugs are installed into the holes.

[0035] like Figures 1-2 As shown, specifically in this embodiment, the angle deflection monitoring unit consists of two differentially configured displacement sensors 9, namely a right displacement sensor 91 and a left displacement sensor 92. Both differentially configured displacement sensors are fixed on the housing 10. Preferably, the two differentially configured displacement sensors 9 are installed at the end of the deflection arm 4 where the metal sheet is located, which facilitates the differential measurement of the displacement of the metal sheet on the deflection arm 4, thereby measuring the current deflection angle of the reflector 11. The measurement signal is then output to an external controller, which performs high-precision closed-loop control according to the mission objective of the rotating mirror device, thereby improving the measurement accuracy.

[0036] The angle deflection monitoring unit is a capacitive sensor, an inductive sensor, an eddy current sensor, a laser interferometric displacement measurement sensor, or other optical precision angle measurement unit.

[0037] Working principle:

[0038] like Figure 3 As shown, when the redundant drive unit outputs driving force, i.e., when either the lower actuator 81 or the upper actuator 82 starts driving, the differential lever 5 tilts, causing the decoupling arm 6 to bend in a direction perpendicular to the motion plane of the yaw arm 4. The resulting parasitic force is perpendicular to the motion plane of the yaw arm 4 and will not cause longitudinal displacement of the reflector 11; Figure 3 As shown, when the yaw arm 4 rotates through a set angle during driving, the position where the yaw arm 4 is connected to the decoupling arm 6 is subjected to significant force, causing the decoupling arm 6 to bend in the motion plane of the yaw arm 4 to adapt to the force. During the driving process, the deformation of the decoupling arm 6 in the motion plane of the yaw arm 4 and the deformation perpendicular to the motion plane of the yaw arm 4 are both in the flexible direction designed for the decoupling arm 6, and it is always rigidly connected in the direction in which pure torque is applied to the yaw arm 4, in order to reduce the longitudinal parasitic displacement on the reflector 11.

[0039] In the description of this invention, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms describing positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances. In addition, if the embodiments of this invention involve descriptions of "first," "second," etc., such descriptions are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of those features. Furthermore, the meaning of "and / or" throughout the text is to include three parallel solutions. Taking "A and / or B" as an example, it includes solution A, or solution B, or a solution that simultaneously satisfies A and B.

[0040] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention, or direct / indirect applications in other related technical fields, should be included within the scope of protection of the claims of the present invention.

Claims

1. A near-zero longitudinal displacement precision rotating mirror based on driving force decoupling, characterized in that, It includes a one-dimensional angle deflection unit, a housing (10), a reflector (11), a redundant drive unit, a differential bar (5), and a decoupling arm (6); The one-dimensional angle deflection unit includes a rigid base (2) and a deflection arm (4). The rigid base (2) is rotatably connected to the outer shell (10). The reflector (11) and the deflection arm (4) are respectively disposed on both sides of the rigid base (2). The redundant drive unit is mounted on the housing (10), the differential rod (5) is connected to the drive end of the redundant drive unit, and the decoupling arm (6) is connected between the differential rod (5) and the yaw arm (4). The differential lever (5) is arranged perpendicular to the yaw arm (4), and the decoupling arm (6) is arranged perpendicular to both the differential lever (5) and the yaw arm (4).

2. A near-zero longitudinal displacement precision rotating mirror based on driving force decoupling according to claim 1, characterized in that, A rigid frame (1) is provided between the outer shell (10) and the rigid base (2), and the rigid frame (1) and the rigid base (2) are rotatably connected by two spoke-shaped flexible hinges (3).

3. A near-zero longitudinal displacement precision rotating mirror based on driving force decoupling according to claim 2, characterized in that, The two spoke-type flexible hinges (3) are symmetrically arranged on the rigid frame (1), and the axes of the two spoke-type flexible hinges (3) pass through the center of the mirror surface of the reflector (11).

4. A near-zero longitudinal displacement precision rotating mirror based on driving force decoupling according to claim 3, characterized in that, The connection surface between the rigid frame (1) and the outer shell (10) is arranged parallel to the mirror surface of the reflector (11).

5. A near-zero longitudinal displacement precision rotating mirror based on driving force decoupling according to claim 1, characterized in that, The decoupling arm (6) is a multi-segment flexible structure.

6. A near-zero longitudinal displacement precision rotating mirror based on driving force decoupling according to claim 5, characterized in that, The decoupling arm (6) is connected to the swing arm (4) at the end of the connection seat, and the connection seat is provided with two plugs. The swing arm (4) is provided with two holes, and the plugs are installed into the holes.

7. A near-zero longitudinal displacement precision rotating mirror based on driving force decoupling according to claim 1, characterized in that, The redundant drive unit includes two actuators (8), the drive ends of the two actuators (8) are connected to both ends of the differential lever (5), and the decoupling arm (6) is connected to the center of the differential lever (5).

8. A near-zero longitudinal displacement precision rotating mirror based on driving force decoupling according to claim 7, characterized in that, The differential lever (5) is flexibly connected to the actuator (8).

9. A near-zero longitudinal displacement precision rotating mirror based on driving force decoupling according to any one of claims 1-8, characterized in that, An angle deflection monitoring unit is provided between the deflection arm (4) and the outer shell (10), and the angle deflection monitoring unit is used to measure the deflection angle of the reflector (11).

10. A near-zero longitudinal displacement precision rotating mirror based on driving force decoupling according to claim 9, characterized in that, A thin metal sheet is provided between the yaw arm (4) and the angle deflection monitoring unit.

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